Minor subscribed for subscription

My 13 year old son has accidentally signed up for a one-year contract for After Effects. How do Adobe control purchases by minors? He tried to cancel the subscription and is now being charged a cancellation fee. He has a credit card with a small amount on it for direct purchases but how is it possible that he signed up for a one-year subscription? How can this fee be reversed? Can I email anyone to help with this? He used his email for this subscription.